In installations for treating large quantities of gas, produced, for example, as waste gas in combustion processes, in particular for removing environmentally polluting compounds, such as dioxins, furans, sulfur compounds, chlorine compounds, nitrogen compounds, hydrocarbons, heavy metals and/or other components, on a bulk material, one substantial problem consists of the large surface area of the bulk material layer, which is occasionally also referred to as “filter.” Indeed, it is desirable to keep the resistance to flow through the bulk material layer small, while at the same time ensuring a consistent high treatment quality throughout the entire filter cross section. To achieve this, the bulk material, if it is to be used in countercurrent with respect to the fluid to be treated, which is a particularly effective method, must be repeatedly and evenly removed at the floor of the bulk material layer, the feed inlet floor, while fresh bulk material is delivered evenly distributed over the surface of the bed, in a bulk material portion exchange. This problem has been solved on a large industrial scale by means of so-called moving bed reactors, as described in the Patents WO 88/08746, WO 91/12069 and EP 0 472 565.
With these known methods, devices and installations, the bulk material is supplied through bulk material reservoir bin and bulk material distribution floors, which are arranged immediately above each bulk material bed. The bulk material unloading openings of the bulk material distribution floors consist of permanently open pipe mouths, where a cone of bulk material forms under each mouth. Since these mouth openings are evenly distributed over the bed cross section, the bulk material bed surface consists of a multitude of such bulk material cones. The space which necessarily remains between the bulk material bed surface and the bulk material distribution floor of each bed acts as a gas collecting space, which space is connected via a closable opening in the lateral wall of the container (reactor) which receives the bulk material bed with a gas collection or exhaust channel, into which the combined waste gas streams of all the beds flow. As a result of the permanently open mouth or discharge openings of the bulk material distribution floor, the fluid to be treated can also penetrate into the bulk material reservoir bin. Therefore, special steps must be taken so that the refill openings of the bulk material reservoir bin are always closed with sufficient seal and that any treated gases which penetrate into the reservoir bin do not cause any undesired reactions in the reservoir bins, for example, as a result of oxygen containing creep flow, so-called hot spots.
An additional problem consists in the fact that the suitability of the available treatment bulk materials is highly variable and, in the case of particularly high concentrations of fluid components to be treated and/or great differences between the fluid components to be treated—it is not sufficient to achieve the desired treatment result in a single processing step.
An additional problem in the mentioned fluid treatment installations consists in the fact that the type of distribution of the bulk material on the reactor beds and/or the application of the bulk material results in a relatively rigid establishment of a predetermined process type in the fluid treatment sequence.